Adasaurus
Encyclopedia
Adasaurus is a genus
of dromaeosaurid theropod dinosaur
from the Late Cretaceous
Period of what is now Central Asia
. It was a small bipedal carnivore
with a sickle-shaped claw
on the second toe of each hind foot. An adult was perhaps about 1.8 m (5.9 ft) long.
Ada is an evil spirit in the national mythology
of Mongolia
. The name also includes the Greek
word sauros meaning 'lizard', the most common suffix used in dinosaur names. There is one species
(A. mongoliensis), named after the country of Mongolia, where the fossil was found. Both genus and species were named and described in 1983 by famous Mongolian paleontologist Rinchen Barsbold.
In 1988, in his book Predatory Dinosaurs of the World, Gregory S. Paul
classified this genus as a species of the North American dromaeosaurid Dromaeosaurus
, resulting in the new combination of Dromaeosaurus mongoliensis. However, to date, this re-classification has not been adopted by other researchers.
Adasaurus is a member of Dromaeosauridae, a theropod family thought to be very closely related to birds. Relationships within the family are poorly understood, but Adasaurus seems to be a member of the subfamily Dromaeosaurinae, along with the Mongolian Achillobator
and several North American species. Other dromaeosaurids include Deinonychus
, Velociraptor
, Microraptor
, and Buitreraptor
. Adasaurus is unique among dromaeosaurids in having much smaller sickle-claws on its hind feet.
Two specimens of Adasaurus have been found, both from the Nemegt Formation
of Bayankhongor Province in Mongolia
. The holotype
, IGM 100/20, is an incomplete skeleton with partial skull
, including the vertebral column except the back of the tail, all three bones of the pelvis
, the shoulder girdle and the hindlimbs. The second specimen, the paratype
IGM 100/51 also described in the original paper, consists of the back end of another skeleton, including the hindlimbs. Both specimens are currently in the collection of the Mongolian Geological Institute in Ulaanbaatar
, Mongolia.
The age of the Nemegt, like most of Mongolia's Late Cretaceous
sediments, is not known for certain, but it is commonly thought to belong to the Maastrichtian
stage of the Late Cretaceous Period. Therefore the Nemegt was deposited somewhere between 74 and 65 million years ago. Other dinosaurs found in this formation
include Tarbosaurus
, Anserimimus
, Zanabazar
, and Saurolophus
.
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of dromaeosaurid theropod dinosaur
Dinosaur
Dinosaurs are a diverse group of animals of the clade and superorder Dinosauria. They were the dominant terrestrial vertebrates for over 160 million years, from the late Triassic period until the end of the Cretaceous , when the Cretaceous–Paleogene extinction event led to the extinction of...
from the Late Cretaceous
Cretaceous
The Cretaceous , derived from the Latin "creta" , usually abbreviated K for its German translation Kreide , is a geologic period and system from circa to million years ago. In the geologic timescale, the Cretaceous follows the Jurassic period and is followed by the Paleogene period of the...
Period of what is now Central Asia
Central Asia
Central Asia is a core region of the Asian continent from the Caspian Sea in the west, China in the east, Afghanistan in the south, and Russia in the north...
. It was a small bipedal carnivore
Carnivore
A carnivore meaning 'meat eater' is an organism that derives its energy and nutrient requirements from a diet consisting mainly or exclusively of animal tissue, whether through predation or scavenging...
with a sickle-shaped claw
Claw
A claw is a curved, pointed appendage, found at the end of a toe or finger in most mammals, birds, and some reptiles. However, the word "claw" is also often used in reference to an invertebrate. Somewhat similar fine hooked structures are found in arthropods such as beetles and spiders, at the end...
on the second toe of each hind foot. An adult was perhaps about 1.8 m (5.9 ft) long.
Ada is an evil spirit in the national mythology
Mythology
The term mythology can refer either to the study of myths, or to a body or collection of myths. As examples, comparative mythology is the study of connections between myths from different cultures, whereas Greek mythology is the body of myths from ancient Greece...
of Mongolia
Mongolia
Mongolia is a landlocked country in East and Central Asia. It is bordered by Russia to the north and China to the south, east and west. Although Mongolia does not share a border with Kazakhstan, its western-most point is only from Kazakhstan's eastern tip. Ulan Bator, the capital and largest...
. The name also includes the Greek
Ancient Greek
Ancient Greek is the stage of the Greek language in the periods spanning the times c. 9th–6th centuries BC, , c. 5th–4th centuries BC , and the c. 3rd century BC – 6th century AD of ancient Greece and the ancient world; being predated in the 2nd millennium BC by Mycenaean Greek...
word sauros meaning 'lizard', the most common suffix used in dinosaur names. There is one species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
(A. mongoliensis), named after the country of Mongolia, where the fossil was found. Both genus and species were named and described in 1983 by famous Mongolian paleontologist Rinchen Barsbold.
In 1988, in his book Predatory Dinosaurs of the World, Gregory S. Paul
Gregory S. Paul
Gregory Scott Paul is a freelance researcher, author and illustrator who works in paleontology, and more recently has examined sociology and theology. He is best known for his work and research on theropod dinosaurs and his detailed illustrations, both live and skeletal...
classified this genus as a species of the North American dromaeosaurid Dromaeosaurus
Dromaeosaurus
Dromaeosaurus was a genus of theropod dinosaur which lived during the Late Cretaceous period , sometime between 76.5 and 74.8 million years ago, in the western United States and Alberta, Canada. The name means 'running lizard'....
, resulting in the new combination of Dromaeosaurus mongoliensis. However, to date, this re-classification has not been adopted by other researchers.
Adasaurus is a member of Dromaeosauridae, a theropod family thought to be very closely related to birds. Relationships within the family are poorly understood, but Adasaurus seems to be a member of the subfamily Dromaeosaurinae, along with the Mongolian Achillobator
Achillobator
Achillobator is a genus of dromaeosaurid theropod dinosaur from the late Cretaceous Period of what is now Mongolia, about 90 million years ago. It was probably an active bipedal predator, hunting with the large sickle-shaped claw on the second toe of each hind foot...
and several North American species. Other dromaeosaurids include Deinonychus
Deinonychus
Deinonychus was a genus of carnivorous dromaeosaurid dinosaur. There is one described species, Deinonychus antirrhopus. This 3.4 meter long dinosaur lived during the early Cretaceous Period, about 115–108 million years ago . Fossils have been recovered from the U.S...
, Velociraptor
Velociraptor
Velociraptor is a genus of dromaeosaurid theropod dinosaur that existed approximately 75 to 71 million years ago during the later part of the Cretaceous Period. Two species are currently recognized, although others have been assigned in the past. The type species is V. mongoliensis; fossils...
, Microraptor
Microraptor
Microraptor is a genus of small, four-winged dromaeosaurid dinosaurs. Numerous well-preserved fossil specimens have been recovered from Liaoning, China...
, and Buitreraptor
Buitreraptor
Buitreraptor is a predatory dromaeosaurid theropod dinosaur from the Cretaceous of Argentina.Buitreraptor was described in 2005. The type species is Buitreraptor gonzalezorum...
. Adasaurus is unique among dromaeosaurids in having much smaller sickle-claws on its hind feet.
Two specimens of Adasaurus have been found, both from the Nemegt Formation
Nemegt Formation
The Nemegt Formation is a geological formation dating from the Late Cretaceous sedimentary from the Gobi Desert of Mongolia. It overlies and sometimes forms folds with the Barun Goyot Formation. It consists of river channel sediments and contains fossils of fish, turtles, crocodilians, birds and a...
of Bayankhongor Province in Mongolia
Mongolia
Mongolia is a landlocked country in East and Central Asia. It is bordered by Russia to the north and China to the south, east and west. Although Mongolia does not share a border with Kazakhstan, its western-most point is only from Kazakhstan's eastern tip. Ulan Bator, the capital and largest...
. The holotype
Holotype
A holotype is a single physical example of an organism, known to have been used when the species was formally described. It is either the single such physical example or one of several such, but explicitly designated as the holotype...
, IGM 100/20, is an incomplete skeleton with partial skull
Skull
The skull is a bony structure in the head of many animals that supports the structures of the face and forms a cavity for the brain.The skull is composed of two parts: the cranium and the mandible. A skull without a mandible is only a cranium. Animals that have skulls are called craniates...
, including the vertebral column except the back of the tail, all three bones of the pelvis
Pelvis
In human anatomy, the pelvis is the lower part of the trunk, between the abdomen and the lower limbs .The pelvis includes several structures:...
, the shoulder girdle and the hindlimbs. The second specimen, the paratype
Paratype
Paratype is a technical term used in the scientific naming of species and other taxa of organisms. The exact meaning of the term paratype when it is used in zoology is not the same as the meaning when it is used in botany...
IGM 100/51 also described in the original paper, consists of the back end of another skeleton, including the hindlimbs. Both specimens are currently in the collection of the Mongolian Geological Institute in Ulaanbaatar
Ulaanbaatar
Ulan Bator or Ulaanbaatar is the capital and largest city of Mongolia. An independent municipality, the city is not part of any province, and its population as of 2008 is over one million....
, Mongolia.
The age of the Nemegt, like most of Mongolia's Late Cretaceous
Late Cretaceous
The Late Cretaceous is the younger of two epochs into which the Cretaceous period is divided in the geologic timescale. Rock strata from this epoch form the Upper Cretaceous series...
sediments, is not known for certain, but it is commonly thought to belong to the Maastrichtian
Maastrichtian
The Maastrichtian is, in the ICS' geologic timescale, the latest age or upper stage of the Late Cretaceous epoch or Upper Cretaceous series, the Cretaceous period or system, and of the Mesozoic era or erathem. It spanned from 70.6 ± 0.6 Ma to 65.5 ± 0.3 Ma...
stage of the Late Cretaceous Period. Therefore the Nemegt was deposited somewhere between 74 and 65 million years ago. Other dinosaurs found in this formation
Geologic formation
A formation or geological formation is the fundamental unit of lithostratigraphy. A formation consists of a certain number of rock strata that have a comparable lithology, facies or other similar properties...
include Tarbosaurus
Tarbosaurus
Tarbosaurus is a genus of tyrannosaurid theropod dinosaur that flourished in Asia about 70 million years ago, at the end of the Late Cretaceous Period. Fossils have been recovered in Mongolia, with more fragmentary remains found further afield in parts of China. Although many species have been...
, Anserimimus
Anserimimus
Anserimimus is a genus of ornithomimid theropod dinosaur, from the Late Cretaceous Period of what is now Mongolia. It was a lanky, fast-running animal, possibly an omnivore...
, Zanabazar
Zanabazar (dinosaur)
Zanabazar is a genus of troodontid dinosaur, which lived during the Late Cretaceous period in Mongolia.Fossils of this theropod have been found in the Nemegt Formation of Mongolia. Originally classified as a new species of the genus Saurornithoides by Rinchen Barsbold in 1974, based on a small...
, and Saurolophus
Saurolophus
Saurolophus is a genus of large hadrosaurine duckbill that lived about 69.5-68.5 million years ago, in the Late Cretaceous of North America and Asia; it is one of the few genera of dinosaurs known from multiple continents. It is distinguished by a spike-like crest which projects up and back...
.